a phrase that requires an agreement between two or more people that either must be fulfilled or that must be true and if it is not they get rushed(gettin your ass beat by everyone present at the time of the shake)

CJ: SHAKE ON IT YOU LASTED MORE THAN TWO MINUTES WITH HER(puts hand out)
JESSE: ILL SHAKE ON IT I LASTED THREE WHOLE MINUTES:)...(shakes cj's hand)